crates/ide_db/src/defs.rs

   1 //! `NameDefinition` keeps information about the element we want to search references for.
   2 //! The element is represented by `NameKind`. It's located inside some `container` and
   3 //! has a `visibility`, which defines a search scope.
   4 //! Note that the reference search is possible for not all of the classified items.
   5
   6 // FIXME: this badly needs rename/rewrite (matklad, 2020-02-06).
   7
   8 use arrayvec::ArrayVec;
   9 use hir::{
  10     Adt, AsAssocItem, AssocItem, BuiltinAttr, BuiltinType, Const, Field, Function, GenericParam,
  11     HasVisibility, Impl, ItemInNs, Label, Local, MacroDef, Module, ModuleDef, Name, PathResolution,
  12     Semantics, Static, ToolModule, Trait, TypeAlias, Variant, Visibility,
  13 };
  14 use stdx::impl_from;
  15 use syntax::{
  16     ast::{self, AstNode},
  17     match_ast, SyntaxKind, SyntaxNode, SyntaxToken,
  18 };
  19
  20 use crate::RootDatabase;
  21
  22 // FIXME: a more precise name would probably be `Symbol`?
  23 #[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
  24 pub enum Definition {
  25     Macro(MacroDef),
  26     Field(Field),
  27     Module(Module),
  28     Function(Function),
  29     Adt(Adt),
  30     Variant(Variant),
  31     Const(Const),
  32     Static(Static),
  33     Trait(Trait),
  34     TypeAlias(TypeAlias),
  35     BuiltinType(BuiltinType),
  36     SelfType(Impl),
  37     Local(Local),
  38     GenericParam(GenericParam),
  39     Label(Label),
  40     BuiltinAttr(BuiltinAttr),
  41     ToolModule(ToolModule),
  42 }
  43
  44 impl Definition {
  45     pub fn canonical_module_path(&self, db: &RootDatabase) -> Option<impl Iterator<Item = Module>> {
  46         self.module(db).map(|it| it.path_to_root(db).into_iter().rev())
  47     }
  48
  49     pub fn module(&self, db: &RootDatabase) -> Option<Module> {
  50         let module = match self {
  51             Definition::Macro(it) => it.module(db)?,
  52             Definition::Module(it) => it.parent(db)?,
  53             Definition::Field(it) => it.parent_def(db).module(db),
  54             Definition::Function(it) => it.module(db),
  55             Definition::Adt(it) => it.module(db),
  56             Definition::Const(it) => it.module(db),
  57             Definition::Static(it) => it.module(db),
  58             Definition::Trait(it) => it.module(db),
  59             Definition::TypeAlias(it) => it.module(db),
  60             Definition::Variant(it) => it.module(db),
  61             Definition::SelfType(it) => it.module(db),
  62             Definition::Local(it) => it.module(db),
  63             Definition::GenericParam(it) => it.module(db),
  64             Definition::Label(it) => it.module(db),
  65             Definition::BuiltinAttr(_) | Definition::BuiltinType(_) | Definition::ToolModule(_) => {
  66                 return None
  67             }
  68         };
  69         Some(module)
  70     }
  71
  72     pub fn visibility(&self, db: &RootDatabase) -> Option<Visibility> {
  73         let vis = match self {
  74             Definition::Field(sf) => sf.visibility(db),
  75             Definition::Module(it) => it.visibility(db),
  76             Definition::Function(it) => it.visibility(db),
  77             Definition::Adt(it) => it.visibility(db),
  78             Definition::Const(it) => it.visibility(db),
  79             Definition::Static(it) => it.visibility(db),
  80             Definition::Trait(it) => it.visibility(db),
  81             Definition::TypeAlias(it) => it.visibility(db),
  82             Definition::Variant(it) => it.visibility(db),
  83             Definition::BuiltinType(_) => Visibility::Public,
  84             Definition::Macro(_) => return None,
  85             Definition::BuiltinAttr(_)
  86             | Definition::ToolModule(_)
  87             | Definition::SelfType(_)
  88             | Definition::Local(_)
  89             | Definition::GenericParam(_)
  90             | Definition::Label(_) => return None,
  91         };
  92         Some(vis)
  93     }
  94
  95     pub fn name(&self, db: &RootDatabase) -> Option<Name> {
  96         let name = match self {
  97             Definition::Macro(it) => it.name(db)?,
  98             Definition::Field(it) => it.name(db),
  99             Definition::Module(it) => it.name(db)?,
 100             Definition::Function(it) => it.name(db),
 101             Definition::Adt(it) => it.name(db),
 102             Definition::Variant(it) => it.name(db),
 103             Definition::Const(it) => it.name(db)?,
 104             Definition::Static(it) => it.name(db),
 105             Definition::Trait(it) => it.name(db),
 106             Definition::TypeAlias(it) => it.name(db),
 107             Definition::BuiltinType(it) => it.name(),
 108             Definition::SelfType(_) => return None,
 109             Definition::Local(it) => it.name(db)?,
 110             Definition::GenericParam(it) => it.name(db),
 111             Definition::Label(it) => it.name(db),
 112             Definition::BuiltinAttr(_) => return None, // FIXME
 113             Definition::ToolModule(_) => return None,  // FIXME
 114         };
 115         Some(name)
 116     }
 117 }
 118
 119 pub enum IdentClass {
 120     NameClass(NameClass),
 121     NameRefClass(NameRefClass),
 122 }
 123
 124 impl IdentClass {
 125     pub fn classify_node(sema: &Semantics<RootDatabase>, node: &SyntaxNode) -> Option<IdentClass> {
 126         match_ast! {
 127             match node {
 128                 ast::Name(name) => NameClass::classify(sema, &name).map(IdentClass::NameClass),
 129                 ast::NameRef(name_ref) => NameRefClass::classify(sema, &name_ref).map(IdentClass::NameRefClass),
 130                 ast::Lifetime(lifetime) => {
 131                     NameClass::classify_lifetime(sema, &lifetime)
 132                         .map(IdentClass::NameClass)
 133                         .or_else(|| NameRefClass::classify_lifetime(sema, &lifetime).map(IdentClass::NameRefClass))
 134                 },
 135                 _ => None,
 136             }
 137         }
 138     }
 139
 140     pub fn classify_token(
 141         sema: &Semantics<RootDatabase>,
 142         token: &SyntaxToken,
 143     ) -> Option<IdentClass> {
 144         let parent = token.parent()?;
 145         Self::classify_node(sema, &parent)
 146     }
 147
 148     pub fn definitions(self) -> ArrayVec<Definition, 2> {
 149         let mut res = ArrayVec::new();
 150         match self {
 151             IdentClass::NameClass(NameClass::Definition(it) | NameClass::ConstReference(it)) => {
 152                 res.push(it)
 153             }
 154             IdentClass::NameClass(NameClass::PatFieldShorthand { local_def, field_ref }) => {
 155                 res.push(Definition::Local(local_def));
 156                 res.push(Definition::Field(field_ref));
 157             }
 158             IdentClass::NameRefClass(NameRefClass::Definition(it)) => res.push(it),
 159             IdentClass::NameRefClass(NameRefClass::FieldShorthand { local_ref, field_ref }) => {
 160                 res.push(Definition::Local(local_ref));
 161                 res.push(Definition::Field(field_ref));
 162             }
 163         }
 164         res
 165     }
 166 }
 167
 168 /// On a first blush, a single `ast::Name` defines a single definition at some
 169 /// scope. That is, that, by just looking at the syntactical category, we can
 170 /// unambiguously define the semantic category.
 171 ///
 172 /// Sadly, that's not 100% true, there are special cases. To make sure that
 173 /// callers handle all the special cases correctly via exhaustive matching, we
 174 /// add a [`NameClass`] enum which lists all of them!
 175 ///
 176 /// A model special case is `None` constant in pattern.
 177 #[derive(Debug)]
 178 pub enum NameClass {
 179     Definition(Definition),
 180     /// `None` in `if let None = Some(82) {}`.
 181     /// Syntactically, it is a name, but semantically it is a reference.
 182     ConstReference(Definition),
 183     /// `field` in `if let Foo { field } = foo`. Here, `ast::Name` both introduces
 184     /// a definition into a local scope, and refers to an existing definition.
 185     PatFieldShorthand {
 186         local_def: Local,
 187         field_ref: Field,
 188     },
 189 }
 190
 191 impl NameClass {
 192     /// `Definition` defined by this name.
 193     pub fn defined(self) -> Option<Definition> {
 194         let res = match self {
 195             NameClass::Definition(it) => it,
 196             NameClass::ConstReference(_) => return None,
 197             NameClass::PatFieldShorthand { local_def, field_ref: _ } => {
 198                 Definition::Local(local_def)
 199             }
 200         };
 201         Some(res)
 202     }
 203
 204     pub fn classify(sema: &Semantics<RootDatabase>, name: &ast::Name) -> Option<NameClass> {
 205         let _p = profile::span("classify_name");
 206
 207         let parent = name.syntax().parent()?;
 208
 209         let definition = match_ast! {
 210             match parent {
 211                 ast::Item(it) => classify_item(sema, it)?,
 212                 ast::IdentPat(it) => return classify_ident_pat(sema, it),
 213                 ast::Rename(it) => classify_rename(sema, it)?,
 214                 ast::SelfParam(it) => Definition::Local(sema.to_def(&it)?),
 215                 ast::RecordField(it) => Definition::Field(sema.to_def(&it)?),
 216                 ast::Variant(it) => Definition::Variant(sema.to_def(&it)?),
 217                 ast::TypeParam(it) => Definition::GenericParam(sema.to_def(&it)?.into()),
 218                 ast::ConstParam(it) => Definition::GenericParam(sema.to_def(&it)?.into()),
 219                 _ => return None,
 220             }
 221         };
 222         return Some(NameClass::Definition(definition));
 223
 224         fn classify_item(sema: &Semantics<RootDatabase>, item: ast::Item) -> Option<Definition> {
 225             let definition = match item {
 226                 ast::Item::MacroRules(it) => {
 227                     Definition::Macro(sema.to_def(&ast::Macro::MacroRules(it))?)
 228                 }
 229                 ast::Item::MacroDef(it) => {
 230                     Definition::Macro(sema.to_def(&ast::Macro::MacroDef(it))?)
 231                 }
 232                 ast::Item::Const(it) => Definition::Const(sema.to_def(&it)?),
 233                 ast::Item::Fn(it) => {
 234                     let def = sema.to_def(&it)?;
 235                     def.as_proc_macro(sema.db)
 236                         .map(Definition::Macro)
 237                         .unwrap_or(Definition::Function(def))
 238                 }
 239                 ast::Item::Module(it) => Definition::Module(sema.to_def(&it)?),
 240                 ast::Item::Static(it) => Definition::Static(sema.to_def(&it)?),
 241                 ast::Item::Trait(it) => Definition::Trait(sema.to_def(&it)?),
 242                 ast::Item::TypeAlias(it) => Definition::TypeAlias(sema.to_def(&it)?),
 243                 ast::Item::Enum(it) => Definition::Adt(hir::Adt::Enum(sema.to_def(&it)?)),
 244                 ast::Item::Struct(it) => Definition::Adt(hir::Adt::Struct(sema.to_def(&it)?)),
 245                 ast::Item::Union(it) => Definition::Adt(hir::Adt::Union(sema.to_def(&it)?)),
 246                 _ => return None,
 247             };
 248             Some(definition)
 249         }
 250
 251         fn classify_ident_pat(
 252             sema: &Semantics<RootDatabase>,
 253             ident_pat: ast::IdentPat,
 254         ) -> Option<NameClass> {
 255             if let Some(def) = sema.resolve_bind_pat_to_const(&ident_pat) {
 256                 return Some(NameClass::ConstReference(Definition::from(def)));
 257             }
 258
 259             let local = sema.to_def(&ident_pat)?;
 260             let pat_parent = ident_pat.syntax().parent();
 261             if let Some(record_pat_field) = pat_parent.and_then(ast::RecordPatField::cast) {
 262                 if record_pat_field.name_ref().is_none() {
 263                     if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
 264                         return Some(NameClass::PatFieldShorthand {
 265                             local_def: local,
 266                             field_ref: field,
 267                         });
 268                     }
 269                 }
 270             }
 271             Some(NameClass::Definition(Definition::Local(local)))
 272         }
 273
 274         fn classify_rename(
 275             sema: &Semantics<RootDatabase>,
 276             rename: ast::Rename,
 277         ) -> Option<Definition> {
 278             if let Some(use_tree) = rename.syntax().parent().and_then(ast::UseTree::cast) {
 279                 let path = use_tree.path()?;
 280                 sema.resolve_path(&path).map(Definition::from)
 281             } else {
 282                 let extern_crate = rename.syntax().parent().and_then(ast::ExternCrate::cast)?;
 283                 let krate = sema.resolve_extern_crate(&extern_crate)?;
 284                 let root_module = krate.root_module(sema.db);
 285                 Some(Definition::Module(root_module))
 286             }
 287         }
 288     }
 289
 290     pub fn classify_lifetime(
 291         sema: &Semantics<RootDatabase>,
 292         lifetime: &ast::Lifetime,
 293     ) -> Option<NameClass> {
 294         let _p = profile::span("classify_lifetime").detail(|| lifetime.to_string());
 295         let parent = lifetime.syntax().parent()?;
 296
 297         if let Some(it) = ast::LifetimeParam::cast(parent.clone()) {
 298             sema.to_def(&it).map(Into::into).map(Definition::GenericParam)
 299         } else if let Some(it) = ast::Label::cast(parent.clone()) {
 300             sema.to_def(&it).map(Definition::Label)
 301         } else {
 302             None
 303         }
 304         .map(NameClass::Definition)
 305     }
 306 }
 307
 308 /// This is similar to [`NameClass`], but works for [`ast::NameRef`] rather than
 309 /// for [`ast::Name`]. Similarly, what looks like a reference in syntax is a
 310 /// reference most of the time, but there are a couple of annoying exceptions.
 311 ///
 312 /// A model special case is field shorthand syntax, which uses a single
 313 /// reference to point to two different defs.
 314 #[derive(Debug)]
 315 pub enum NameRefClass {
 316     Definition(Definition),
 317     FieldShorthand { local_ref: Local, field_ref: Field },
 318 }
 319
 320 impl NameRefClass {
 321     // Note: we don't have unit-tests for this rather important function.
 322     // It is primarily exercised via goto definition tests in `ide`.
 323     pub fn classify(
 324         sema: &Semantics<RootDatabase>,
 325         name_ref: &ast::NameRef,
 326     ) -> Option<NameRefClass> {
 327         let _p = profile::span("classify_name_ref").detail(|| name_ref.to_string());
 328
 329         let parent = name_ref.syntax().parent()?;
 330
 331         if let Some(record_field) = ast::RecordExprField::for_field_name(name_ref) {
 332             if let Some((field, local, _)) = sema.resolve_record_field(&record_field) {
 333                 let res = match local {
 334                     None => NameRefClass::Definition(Definition::Field(field)),
 335                     Some(local) => {
 336                         NameRefClass::FieldShorthand { field_ref: field, local_ref: local }
 337                     }
 338                 };
 339                 return Some(res);
 340             }
 341         }
 342
 343         if let Some(path) = ast::PathSegment::cast(parent.clone()).map(|it| it.parent_path()) {
 344             if path.parent_path().is_none() {
 345                 if let Some(macro_call) = path.syntax().parent().and_then(ast::MacroCall::cast) {
 346                     // Only use this to resolve to macro calls for last segments as qualifiers resolve
 347                     // to modules below.
 348                     if let Some(macro_def) = sema.resolve_macro_call(&macro_call) {
 349                         return Some(NameRefClass::Definition(Definition::Macro(macro_def)));
 350                     }
 351                 }
 352             }
 353             return sema.resolve_path(&path).map(Into::into).map(NameRefClass::Definition);
 354         }
 355
 356         match_ast! {
 357             match parent {
 358                 ast::MethodCallExpr(method_call) => {
 359                     sema.resolve_method_call(&method_call)
 360                         .map(Definition::Function)
 361                         .map(NameRefClass::Definition)
 362                 },
 363                 ast::FieldExpr(field_expr) => {
 364                     sema.resolve_field(&field_expr)
 365                         .map(Definition::Field)
 366                         .map(NameRefClass::Definition)
 367                 },
 368                 ast::RecordPatField(record_pat_field) => {
 369                     sema.resolve_record_pat_field(&record_pat_field)
 370                         .map(Definition::Field)
 371                         .map(NameRefClass::Definition)
 372                 },
 373                 ast::AssocTypeArg(_) => {
 374                     // `Trait<Assoc = Ty>`
 375                     //        ^^^^^
 376                     let containing_path = name_ref.syntax().ancestors().find_map(ast::Path::cast)?;
 377                     let resolved = sema.resolve_path(&containing_path)?;
 378                     if let PathResolution::Def(ModuleDef::Trait(tr)) = resolved {
 379                         // FIXME: resolve in supertraits
 380                         if let Some(ty) = tr
 381                             .items(sema.db)
 382                             .iter()
 383                             .filter_map(|&assoc| match assoc {
 384                                 hir::AssocItem::TypeAlias(it) => Some(it),
 385                                 _ => None,
 386                             })
 387                             .find(|alias| alias.name(sema.db).to_smol_str() == name_ref.text().as_str())
 388                         {
 389                             return Some(NameRefClass::Definition(Definition::TypeAlias(ty)));
 390                         }
 391                     }
 392                     None
 393                 },
 394                 ast::ExternCrate(extern_crate) => {
 395                     let krate = sema.resolve_extern_crate(&extern_crate)?;
 396                     let root_module = krate.root_module(sema.db);
 397                     Some(NameRefClass::Definition(Definition::Module(root_module)))
 398                 },
 399                 _ => None
 400             }
 401         }
 402     }
 403
 404     pub fn classify_lifetime(
 405         sema: &Semantics<RootDatabase>,
 406         lifetime: &ast::Lifetime,
 407     ) -> Option<NameRefClass> {
 408         let _p = profile::span("classify_lifetime_ref").detail(|| lifetime.to_string());
 409         let parent = lifetime.syntax().parent()?;
 410         match parent.kind() {
 411             SyntaxKind::BREAK_EXPR | SyntaxKind::CONTINUE_EXPR => {
 412                 sema.resolve_label(lifetime).map(Definition::Label).map(NameRefClass::Definition)
 413             }
 414             SyntaxKind::LIFETIME_ARG
 415             | SyntaxKind::SELF_PARAM
 416             | SyntaxKind::TYPE_BOUND
 417             | SyntaxKind::WHERE_PRED
 418             | SyntaxKind::REF_TYPE => sema
 419                 .resolve_lifetime_param(lifetime)
 420                 .map(GenericParam::LifetimeParam)
 421                 .map(Definition::GenericParam)
 422                 .map(NameRefClass::Definition),
 423             // lifetime bounds, as in the 'b in 'a: 'b aren't wrapped in TypeBound nodes so we gotta check
 424             // if our lifetime is in a LifetimeParam without being the constrained lifetime
 425             _ if ast::LifetimeParam::cast(parent).and_then(|param| param.lifetime()).as_ref()
 426                 != Some(lifetime) =>
 427             {
 428                 sema.resolve_lifetime_param(lifetime)
 429                     .map(GenericParam::LifetimeParam)
 430                     .map(Definition::GenericParam)
 431                     .map(NameRefClass::Definition)
 432             }
 433             _ => None,
 434         }
 435     }
 436 }
 437
 438 impl_from!(
 439     Field, Module, Function, Adt, Variant, Const, Static, Trait, TypeAlias, BuiltinType, Local,
 440     GenericParam, Label
 441     for Definition
 442 );
 443
 444 impl From<Impl> for Definition {
 445     fn from(impl_: Impl) -> Self {
 446         Definition::SelfType(impl_)
 447     }
 448 }
 449
 450 impl AsAssocItem for Definition {
 451     fn as_assoc_item(self, db: &dyn hir::db::HirDatabase) -> Option<AssocItem> {
 452         match self {
 453             Definition::Function(it) => it.as_assoc_item(db),
 454             Definition::Const(it) => it.as_assoc_item(db),
 455             Definition::TypeAlias(it) => it.as_assoc_item(db),
 456             _ => None,
 457         }
 458     }
 459 }
 460
 461 impl From<AssocItem> for Definition {
 462     fn from(assoc_item: AssocItem) -> Self {
 463         match assoc_item {
 464             AssocItem::Function(it) => Definition::Function(it),
 465             AssocItem::Const(it) => Definition::Const(it),
 466             AssocItem::TypeAlias(it) => Definition::TypeAlias(it),
 467         }
 468     }
 469 }
 470
 471 impl From<PathResolution> for Definition {
 472     fn from(path_resolution: PathResolution) -> Self {
 473         match path_resolution {
 474             PathResolution::Def(def) => def.into(),
 475             PathResolution::AssocItem(item) => {
 476                 let def: ModuleDef = match item {
 477                     hir::AssocItem::Function(it) => it.into(),
 478                     hir::AssocItem::Const(it) => it.into(),
 479                     hir::AssocItem::TypeAlias(it) => it.into(),
 480                 };
 481                 def.into()
 482             }
 483             PathResolution::Local(local) => Definition::Local(local),
 484             PathResolution::TypeParam(par) => Definition::GenericParam(par.into()),
 485             PathResolution::Macro(def) => Definition::Macro(def),
 486             PathResolution::SelfType(impl_def) => Definition::SelfType(impl_def),
 487             PathResolution::ConstParam(par) => Definition::GenericParam(par.into()),
 488             PathResolution::BuiltinAttr(attr) => Definition::BuiltinAttr(attr),
 489             PathResolution::ToolModule(tool) => Definition::ToolModule(tool),
 490         }
 491     }
 492 }
 493
 494 impl From<ModuleDef> for Definition {
 495     fn from(def: ModuleDef) -> Self {
 496         match def {
 497             ModuleDef::Module(it) => Definition::Module(it),
 498             ModuleDef::Function(it) => Definition::Function(it),
 499             ModuleDef::Adt(it) => Definition::Adt(it),
 500             ModuleDef::Variant(it) => Definition::Variant(it),
 501             ModuleDef::Const(it) => Definition::Const(it),
 502             ModuleDef::Static(it) => Definition::Static(it),
 503             ModuleDef::Trait(it) => Definition::Trait(it),
 504             ModuleDef::TypeAlias(it) => Definition::TypeAlias(it),
 505             ModuleDef::BuiltinType(it) => Definition::BuiltinType(it),
 506         }
 507     }
 508 }
 509
 510 impl From<Definition> for Option<ItemInNs> {
 511     fn from(def: Definition) -> Self {
 512         let item = match def {
 513             Definition::Module(it) => ModuleDef::Module(it),
 514             Definition::Function(it) => ModuleDef::Function(it),
 515             Definition::Adt(it) => ModuleDef::Adt(it),
 516             Definition::Variant(it) => ModuleDef::Variant(it),
 517             Definition::Const(it) => ModuleDef::Const(it),
 518             Definition::Static(it) => ModuleDef::Static(it),
 519             Definition::Trait(it) => ModuleDef::Trait(it),
 520             Definition::TypeAlias(it) => ModuleDef::TypeAlias(it),
 521             Definition::BuiltinType(it) => ModuleDef::BuiltinType(it),
 522             _ => return None,
 523         };
 524         Some(ItemInNs::from(item))
 525     }
 526 }